Both Ukrainian armed forces and separatists controlling parts of eastern Ukraine spoke of renewed shelling in the region early Thursday.
Video and images confirmed by CNN show that a pre-school in Ukrainian-controlled territory was hit by a shell Thursday.
The Ukrainian armed forces said that "Russian occupation troops shelled the settlement of Stanytsia Luhanska."
As a result of the application of heavy artillery weapons by terrorists, the shells hit the kindergarten facility. According to preliminary data, two civilians received injuries."
In a statement on Twitter, Dmytro Kuleba, Ukraine's foreign minister, said the village of Stanytsia Luhanska "was shelled with heavy weapons from the occupied territory of the Donbas. Civilian infrastructure damaged. We call on all partners to swiftly condemn this severe violation of Minsk agreements by Russia amid an already tense security situation."
Kremlin spokesperson Dmitry Peskov on Thursday said the reports of shellfire were a matter of "very, very deep concern" but added that there were no plans to discuss the matter with the Ukrainian government.
"We have repeatedly warned that the excessive concentration of the armed forces of Ukraine in the vicinity of the lines of contact, combined with possible provocations, could pose a terrible threat," Peskov said.
"We now see that these provocations are underway, we see reports from representatives of the [separatists] republics that there is an exchange of blows on the lines of contact, and that the first blow came from Ukraine, this is alarming. We hope that our opponents from Western capitals, the United States, and NATO countries will use all their influence to warn the Kyiv authorities about further escalation," he added.
CNN has established that the school is less than five kilometers (about three miles) from what is known as the Line of Contact, which separates the two sides. CNN has not established who initiated the exchange of fire.
Pro-Russian separatists said different residential areas had come under fire from the Ukrainian military, near Donetsk and Luhansk.
CNN contacted a resident of Mariinka near Donetsk who had posted a video that included the sound of heavy explosions early Thursday.
She told CNN that the worst period was between 8:00 a.m. and 9:00 a.m. local time. She said people were staying indoors.
Violations of the ceasefire agreement in the region occur regularly, sometimes involving the use of heavy weaponry.
Correction: An earlier version of this post included the wrong distance of the school from the frontlines. The school is less than five kilometers from the Line of Contact.